JPH06179792A - Methacrylic impact modifier and resin composition - Google Patents

Abstract

PURPOSE:To provide a methacrylic impact modifier composed of a specific multilayer structure polymer, having excellent initial impact strength and capable of keeping excellent optical properties and impact strength even after weathering test and, accordingly, suitable for imparting methacrylic resin, etc., with impact resistance. CONSTITUTION:The modifier is a multilayer structure polymer composed of a combination of (A) 10-90 pts.wt. of a soft polymer layer obtained by the polymerization of a mixture of 9.9-90wt.% of isoprene, 9.9-90wt.% of an alkyl acrylate having 1-12C alkyl group, 0-30wt.% of a copolymerizable unsaturated monomer and 1-10wt.% of a polyfunctional cross-linking monomer and/or a polyfunctional grafting monomer (hereinafter referred to as polyfunctional monomer) and (B) 10-90 pts.wt. of a hard polymer layer obtained by the polymerization of a mixture of 50-100wt.% of an alkyl methacrylate containing 1-4C alkyl group, 0-50wt.% of a copolymerizable unsaturated monomer and 0-5wt.% of a polyfunctional monomer and having an outermost layer consisting of (C) a hard polymer layer obtained by the polymerization of a mixture of 50-100wt.% of an alkyl methacrylate containing 1-4C alkyl group and 0-50wt.% of a copolymerizable unsaturated monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methacrylic impact resistance improver and an impact resistance resin composition. More specifically, it has good impact resistance and excellent optical properties and impact even after a weather resistance test. TECHNICAL FIELD The present invention relates to a methacrylic impact resistance improver characterized by retaining strength, and a methacrylic impact resistance resin composition.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resin is colorless and transparent, has a beautiful appearance and weather resistance, and is easy to mold. Therefore, electrical parts such as louvers, tail lamps, lenses, tableware, vehicle parts, optical applications, decorations, miscellaneous goods, and signboards. However, its strength against impact is not always sufficient, and many improvements and modifications have been studied, and it has been commercialized as a methacrylic impact resistant resin.

The current methacrylic impact-resistant resins have rubber-based fine particles which impart impact properties uniformly dispersed in a general-purpose methacrylic resin, and these rubber-based fine particles have various physical properties of the methacrylic impact-resistant resin. It is no exaggeration to say that it depends. In methacrylic impact-resistant resins, butyl acrylate polymers or butadiene-butyl acrylate copolymers are widely used as rubber-based fine particles from the viewpoints of transparency and weather resistance. And, it is generally considered that acrylic ester type rubber fine particles such as butyl acrylate have good weather resistance, but this is not always the case. Impact resin has good optical properties such as hue,
Almost no change is observed, but impact strength may be remarkably reduced depending on the particle size of rubber. On the other hand, the butadiene-butyl acrylate copolymer type impact resistant resin has good retention of impact strength in a weather resistance test, but the hue tends to be lower than that of the butyl acrylate polymer type impact resistant resin. The reality is that nothing is satisfied.

[0004]

The present invention relates to a methacrylic impact resistance improver and a resin composition, and more specifically, it has good impact resistance and excellent optical properties and impact even after a weather resistance test. An object of the present invention is to provide a methacrylic impact resistance improver and a methacrylic impact resistance resin composition that retain strength.

[0005]

The present inventors have found that the methacrylic impact resistance improver has good impact resistance and retains excellent optical properties and impact strength even after a weather resistance test, and As a result of earnest research on the methacrylic impact-resistant resin composition, a specific multilayer structure polymer in which the soft polymer layer is an isoprene-alkyl acrylate copolymer was found, and the present invention was completed. That is, an object of the present invention is to provide 9.9 to 90% by weight of isoprene and 9.9 to 90% by weight of at least one alkyl acrylate ester whose alkyl group has 1 to 12 carbon atoms, which can be copolymerized with these. Unsaturated monomer 0 to 30% by weight, polyfunctional crosslinking monomer and / or polyfunctional grafting monomer 0.1 to 10
10 to 90 parts by weight of at least one soft polymer layer obtained by polymerizing a monomer mixture of 10% by weight, and at least one methacrylic acid alkyl ester in which the alkyl group has 1 to 4 carbon atoms 50 to 100 By weight, a monomer mixture consisting of 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, 0 to 5% by weight of a polyfunctional crosslinking monomer and / or a polyfunctional grafting monomer is polymerized. 50 to 100% by weight of at least one methacrylic acid alkyl ester whose outermost layer has a carbon number of 1 to 4 in combination with 10 to 90 parts by weight of at least one hard polymer layer, Improvement of methacrylic impact resistance, which is a multi-layered polymer comprising a hard polymer layer obtained by polymerizing a monomer mixture consisting of 0 to 50% by weight of an unsaturated monomer copolymerizable with these. , And it is achieved by methacrylic impact-resistant resin composition comprising the methacrylic impact modifier and a thermoplastic polymer.

A known emulsion polymerization method is used for the multilayer structure polymer of the present invention. The type and amount of the emulsifier used in the emulsion polymerization are selected depending on the stability of the polymerization system, the target particle size, etc., but a known emulsifier such as an anionic surfactant, a cationic surfactant, or a nonionic surfactant is used. They can be used alone or in combination, and anionic surfactants are particularly preferable. The polymerization initiator used for emulsion polymerization is not particularly limited, and persulfate-based or redox-based initiators are used. Further, a chain transfer agent such as alkyl mercaptan is used if necessary.

In emulsion polymerization, monomers, emulsifiers, polymerization initiators, chain transfer agents and the like are added by any method such as a batch addition method, a divided addition method and a continuous addition method.

The method of uniformly mixing the respective polymer latices obtained by emulsion polymerization and then precipitating and solidifying is not particularly limited, and a salting-out method, an aciding-out method, a spraying method, a freezing method and the like are possible.

The multilayer structure polymer of the present invention comprises at least 1
10 to 90 parts by weight of at least one soft polymer layer and at least 1 layer
10 to 90 parts by weight of a hard polymer layer or more, and the outermost layer is a hard polymer layer. If the soft polymer layer is less than 10 parts by weight, the impact strength is low, which is not preferable. If the hard polymer layer is less than 10 parts by weight, the kneadability with a general-purpose methacrylic resin or the like is deteriorated, which is not preferable.

The soft polymer layer in the multi-layered polymer is composed of isoprene and at least one alkyl acrylate ester having an alkyl group having 1 to 12 carbon atoms.
The composition ratio of isoprene composing the soft polymer layer is 9.9.
% To 90% by weight, more preferably 35 to 80% by weight. If it is less than 10% by weight, impact strength may decrease in the weather resistance test, and if it exceeds 90% by weight, yellowish coloration may occur in the weather resistance test. It is not preferable because it is seen and the hue changes. The composition ratio of the other alkyl acrylate is based on the balance with isoprene forming the soft polymer layer, and in maintaining the transparency of the resin, it is determined by the refractive index of the hard polymer layer. Therefore, the composition ratio of the acrylic acid alkyl ester is 9.9 to 90% by weight,
More preferably, it is 20 to 65% by weight. Contrary to isoprene, if it is less than 9.9% by weight, the hue changes in the weather resistance test, which is not preferable, and if it exceeds 90% by weight, the impact strength may be lowered, which is not preferable. The alkyl acrylate used here is at least one kind having an alkyl group having 1 to 12 carbon atoms, and is methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate. , Benzyl acrylate and the like, and preferably butyl acrylate and 2-ethylhexyl acrylate. As the unsaturated monomer copolymerizable with these, 1,3-
Butadiene, 2,3-butadiene, styrene, α-methylstyrene, vinyltoluene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, acrylonitrile, methacrylonitrile, and the like. Used alone or in combination. Further, the polyfunctional crosslinking monomer and the polyfunctional grafting monomer are 0.1 to 10% by weight, and examples of the polyfunctional crosslinking monomer include ethylene glycol di (meth) acrylate and 1,3- Butylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene and the like, and polyfunctional grafting monomers include allyl methacrylate, allyl acrylate, allyl maleate, allyl fumarate, diallyl fumarate, and triaryl fumarate. Allyl cyanurate and the like can be mentioned, and they can be used alone or in combination.

The hard polymer layer of the multi-layer structure polymer has an alkyl group having 1 to 4 carbon atoms from the viewpoint of transparency and weather resistance.
At least one methacrylic acid alkyl ester 50
.About.100% by weight is used, particularly preferably methyl methacrylate. Monomers copolymerizable with these are 0 to 50% by weight of unsaturated monomers, and 0 to 5% by weight of polyfunctional crosslinking monomers and polyfunctional grafting monomers are alkyl acrylates. All the monomers used in the soft polymer layer containing an ester can be used alone or in combination.

On the other hand, the outermost layer of the multilayer structure polymer is a hard polymer layer from the viewpoint of compatibility with general-purpose methacrylic resins, and the ratio of the outermost layer to the total amount is preferably 10 parts by weight or more. As the monomer constituting the outermost layer, 50 to 100% by weight of at least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms is used in terms of transparency and weather resistance, as in the case of the above-mentioned hard polymer. And particularly preferably methyl methacrylate. The monomer copolymerizable with these is 0 to 50% by weight of an unsaturated monomer, and is used in the hard polymer layer except the polyfunctional crosslinkable monomer and the polyfunctional graft monomer. All the given monomers can be used. Further, from the viewpoint of compatibility with general-purpose methacrylic resin, n
Chain transfer agents such as octyl mercaptan and n-dodecyl mercaptan are preferably used.

The multi-layered polymer of the present invention can be obtained as a polymer latex by sequentially emulsion-polymerizing a monomer mixture for each of these layers.

The methacrylic impact modifier of the present invention means a coagulated powder of the above-mentioned multi-layered polymer latex, a coagulated powder of a mixture of different multi-layered polymer latexes, a multi-layered polymer latex and a hard methacrylic resin. It may be a coagulated powder of a latex mixture, and a mixture of different multi-layered polymer coagulated powders, or pellets thereof, etc., but impact resistance by blending with a general-purpose methacrylic resin or other thermoplastic resin To give any methacrylic impact-resistant resin composition. It is also possible to impart gloss, impact resistance or weather resistance by blending the methacrylic impact resistance improver of the present invention with a thermoplastic resin such as vinyl chloride resin or ABS resin other than methacrylic resin. .

The impact-resistant resin composition of the present invention comprises a hard methacrylic compound obtained by polymerizing a monomer mixture containing 50% by weight or more of at least one methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. It is a mixture of a polymer based polymer and the above-mentioned methacrylic impact resistance improver or pellets thereof, which can be directly processed into a sheet or a film as an injection molding material or by an extruder. The mixing ratio of the methacrylic polymer and the above methacrylic impact modifier is 1 to 90 parts by weight of the methacrylic impact modifier to 10 to 99 parts by weight of the hard methacrylic polymer, and particularly methacrylic acid. A methacrylic polymer having methyl as a main constituent unit is preferable, and a general-purpose injection molding methacrylic resin is also included.

The injection-molded articles, sheets / films and their processed products obtained from the impact-resistant resin composition of the present invention have good impact resistance and weather resistance in both optical properties such as hue and impact strength. It has excellent properties.

UV absorbers, antioxidants, lubricants, dyes and pigments, etc., which are usually used for methacrylic resins, can be added as required.

[0018]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.
All "%" and "parts" in the examples are "% by weight" and "parts by weight", and the monomer used, the polymerization initiator,
The following are used as abbreviations of chain transfer agents and the like. Methyl methacrylate (MMA), methyl acrylate (MA),
Ethyl acrylate (EA), butyl acrylate (B
A), isoprene (IP), 1,3-butadiene (B
D), styrene (ST), allyl methacrylate (ALM
A), ethylene glycol dimethacrylate (EGDM
A), n-octyl mercaptan (n-OM), sodium stearate (SS), sodium N-lauroyl sarcosinate (LSS), potassium persulfate (KPS).

The horizontal line (-) is used to separate the monomers used for forming the same layer, and the diagonal line (/) is used.
Means the layers are different.

Various physical properties shown in the examples were measured according to the following methods. (1) Izod impact strength (notched); ASTM-
D256 (2) Total light transmittance, haze; ASTM-
D1003 (3 mm thickness) (3) Colorimetric value b: Hunter colorimetric color difference meter (3 mm thickness) (4) Particle diameter: Measured with an electron microscope. (5) Weather resistance test: Accelerated exposure test, exposure time 1000 hrs (Sunshine weather meter) The above (1) to (3) were evaluated. Example 1 In a pressure resistant reaction vessel equipped with a reflux condenser, 140 parts of distilled water and SS
0.4 parts, LSS 0.4 parts, sodium pyrophosphate 0.
5 parts, ferrous sulfate 0.005 parts, dextrose 0.2
Then, 45 parts of BA, 0.7 parts of ALMA, and 0.15 parts of diisopropylbenzene hydroperoxide were added, and the inside of the pressure resistant reaction vessel was replaced with nitrogen, 25 parts of BD was added, and the temperature was raised to 60 ° C. and polymerization was carried out for 2 hours.

Next, 0.12 parts of Rongalite and 60 parts of distilled water were added to the obtained latex and the temperature was lowered to 50 ° C., then 28 parts of MMA, 2 parts of EA, 0.10 part of cumene hydroperoxide, and n-OM0. A monomer mixture consisting of 06 parts was continuously added over 120 minutes, and after the addition was completed, the mixture was kept for 120 minutes to obtain a two-layer structure polymer (A-1). The particle size of the obtained latex was 0.15 μm.

The latex obtained was placed in a stainless steel container and frozen in a freezer under the temperature condition of -20 ° C. Thaw frozen latex at 50 ° C, and then filter to 2
The layer structure polymer (A-1) was separated. Further, after washing with water and dehydration with distilled water three times, it was dried at 60 ° C. for 10 hours.

After drying, the obtained two-layer structure polymer (A-
1) 30 parts and methacrylic resin beads (Kuraray Co., Ltd .; Parapet EH) 70 parts were mixed and melt-kneaded at a cylinder temperature of 250 ° C. using a 50φ sheet extruder,
An extruded plate having a plate thickness of 3 mm was obtained. Table 1 shows the results of evaluation by cutting out test pieces from the obtained extruded plate. Use this test piece as a sunshine weather meter (Suga tester, WEL-S
When subjected to a 2000-hour accelerated exposure test with (UN-HC), the decrease in Izod impact strength and the change in hue were very small.

From the results obtained, the resin composition according to the present invention is excellent in initial impact resistance, shows good impact strength and hue retention even after the weather resistance test, and is clearly improved in weather resistance. I know that Examples 2 to 8 By the same method as in Example 1, multilayer structure polymers (A-2) to (A-5) having different numbers of layers, compositions and particle diameters were obtained. The number of layers, the composition and the particle diameter of these polymers are shown in Table 1. Table 2 shows the evaluation results of the extruded plate having a plate thickness of 3 mm obtained by changing the mixing ratio of each of the obtained multilayer structure polymers and the hard methacrylic resin. The Izod impact strength and hue of the extruded plates obtained in these examples satisfied the present invention, and both weather resistances were good. Injection-molded articles made from pellets having the same composition as these extruded plates also showed the same results as the extruded plates.

Table 1 shows hard methacrylic resins used for blending when polymer powders were extruded by a sheet extruder in Examples.

The hard methacrylic resin (C-1) in Examples 7 to 8 and Comparative Examples 3 and 6 was produced by emulsion polymerization in the same manner as the multilayer structure polymer, and was prepared in a latex state with the multilayer structure polymer. After mixing, it was solidified and taken out for use.

From the obtained results, the resin composition according to the present invention is excellent in initial impact resistance, shows good impact strength and hue retention even after the weather resistance test, and is clearly improved in weather resistance. It is understood that there is. Comparative Example 1 By the same method as in Example 1, multilayer structure polymers (B-1) to (B-2) having different numbers of layers, compositions and particle diameters were obtained. The number of layers, the composition and the particle diameter of these polymers are shown in Table 1. Table 3 shows the evaluation results of the extruded plate having a plate thickness of 3 mm obtained by changing the mixing ratio of each of the obtained multilayer structure polymers and methacrylic resin. In the weather resistance test under accelerated exposure of the extruded plates obtained in these comparative examples, the results satisfying both Izod impact strength and hue were not obtained.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

The methacrylic impact modifier of the present invention,
And this methacrylic impact resistance resin composition consisting of methacrylic impact resistance improver and hard methacrylic polymer is excellent in the initial impact resistance and satisfies both the impact strength and the hue even after the weather resistance test. It has excellent weather resistance and is most suitable for injection molded products, sheets and films and their processed products.

[Procedure amendment]

[Submission date] April 9, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

Various physical properties shown in the examples were measured according to the following methods. (1) Izod impact strength (notched); ASTM-
D256 (2) Total light transmittance, haze; ASTM-D
1003 (3 mm thickness) (3) Colorimetric value b; Hunter colorimetric color difference meter (3 mm thickness) (4) Particle size; Measured by electron microscope (5) Weather resistance test; Accelerated exposure test, exposure time 1000 hrs (Sunshine weather meter) ) Evaluation of the above (1) to (3). Example 1 In a pressure resistant reaction vessel equipped with a reflux condenser, 140 parts of distilled water and SS
0.4 parts, LSS 0.4 parts, sodium pyrophosphate 0.
5 parts, ferrous sulfate 0.005 parts, dextrose 0.2
Then, 45 parts of BA, 0.7 parts of ALMA, and 0.15 parts of diisopropylbenzene hydroperoxide were added, and the interior of the pressure resistant reaction vessel was replaced with nitrogen. Then, 25 parts of IP was added, the temperature was raised to 60 ° C., and polymerization was performed for 2 hours. .

Claims (10)

[Claims] 1. Isoprene 9.9 to 90% by weight and at least one acrylate alkyl ester in which the alkyl group has 1 to 12 carbon atoms 9.9 to 90% by weight, and an unsaturated monomer copolymerizable therewith. 0-30% by weight of a monomer, a polyfunctional crosslinking monomer and / or a polyfunctional grafting monomer 0.1-1
10 to 90 parts by weight of at least one soft polymer layer obtained by polymerizing a monomer mixture of 0% by weight, and at least one methacrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms 50 to 50 parts by weight. Polymerization of a monomer mixture consisting of 100% by weight, 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, 0 to 5% by weight of a polyfunctional crosslinking monomer and / or a polyfunctional grafting monomer. Consisting of 10 to 90 parts by weight of a hard polymer layer of at least one layer
And the outermost layer has at least one methacrylic acid alkyl ester having an alkyl group with 1 to 4 carbon atoms of 50 to 100.
A methacrylic resin having a multi-layer structure comprising a hard polymer layer formed by polymerizing a monomer mixture consisting of 0 to 50% by weight of an unsaturated monomer copolymerizable with the above. Impact modifier. 2. The soft polymer layer comprises 35 to 80% by weight of isoprene and 20 to 65% by weight of at least one alkyl acrylate ester whose alkyl group has 1 to 12 carbon atoms,
By polymerizing a monomer mixture comprising 0 to 30% by weight of an unsaturated monomer copolymerizable with these, a polyfunctional crosslinking monomer and / or 0.1 to 10% by weight of a polyfunctional grafting monomer. The methacrylic impact modifier according to claim 1, wherein 3. The methacrylic impact modifier according to claim 1, wherein the methacrylic acid alkyl ester is methyl methacrylate. 4. The methacrylic impact modifier according to claim 1, wherein the alkyl acrylate is butyl acrylate. 5. The methacrylic impact resistance improver according to claim 1, wherein the ratio of the outermost layer to the total amount is 10 parts by weight or more. 6. The particle diameter of the multi-layer structure polymer is 0.01 to.
The methacrylic impact resistance improver according to claim 1, which has a thickness of 0.5 μm. 7. A two-layer structure polymer in which the inner layer is a soft polymer layer, the outer layer is a hard polymer layer, the inner layer is a hard polymer layer, the intermediate layer is a soft polymer layer, and the outer layer is a hard polymer layer. A layered polymer, or a four-layered polymer in which the inner layer is a soft polymer layer, the second layer is a hard polymer layer, the third layer is a soft polymer layer, and the outer layer is a hard polymer layer. 6. The methacrylic impact resistance improver according to 6. 8. The methacrylic impact resistance improver according to claim 1, wherein an optional polymer layer is present between the respective layers. 9. A thermoplastic polymer of 10 to 99 parts by weight, and a methacrylic impact resistance improver of 1 to 90 according to claim 1.
An impact resistant resin composition consisting of parts by weight. 10. A hard methacrylic polymer obtained by polymerizing a monomer mixture containing 50% by weight or more of at least one methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. The impact resistant resin composition according to claim 9.